WebAssembly: Debugger support

[kumpera]

This issue tracks the pending work to get the debugger to work:

MVP:

• Set and Hit Breakpoints
• Handle page reload
• Fix/workaround asp.net crashes/races when WASM payload is parsed
• Unify debugging engine with sdb
• Single stepping
• Build MonoProxy as a library and ship it on mono-wasm.zip
• Move proxy code to mono repo
• BP manipulation (enable/disable/remove)
• C# Async stepping
• Object inspection (this variable, fields, properties, etc)
• objectGroup support (debugger object lifecycle, so long sessions are possible)
• automated testing
• Release + no debugger build of mono
• Error handling (invalid BP request)

V2:

• Firefox and Edge support
• js async debug integration
• watches
• console eval
• high performance json forwarding

[kumpera]

With #9339 we got bp, stepping and unification done.

[kumpera]

Issues:
#9405
#9406

[kumpera]

Quality of life things:

• Copy the discover feature from the Blazor prototype. It would simplify our OOTB debugger story by removing the URL port rewrite nonsense.
• Validate the downloaded assemblies against what's loaded in the webapp. I frequently forget to reload it after rebuilding locally. 🤦‍♂️

[kumpera]

With #9626 we get the proxy code in the mono repo and the proxy lib shipping with mono-wasm.zip

[kumpera]

Missing from that list: object inspection of maps and arrays

[kumpera]

Object/frame inspection has 3 arguments we currently ignore: ownProperties, accessorPropertiesOnly, generatePreview

[kumpera]

Another thing, we're missing the neat resume overlay on the webpage that regular JS BPs get.

[kumpera]

When describing fields, we need to handle boxed objects.